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Create a tool that projects a laser net to combine with the Light Painting photography technique, so that when projecting this net over a scene, it “seems” to be a wireframing view of a 3D modeled scene.

Solution:

Using only one laser pointer, create a set of horizontal and vertical lines that combined with the photo long exposure will result in a laser net. The laser pointer is moved by two RC servos controlled with a PWM signal generated by a 16F876A PIC microcontroller.
Once the circuit is done, the program can be configured to change laser speed, offset between lines and net size.

For the video I used a 7.4V LiPo battery, the voltage is regulated by a 7805, and the laser pointer uses one of the PIC 5V outputs with a 25 Ohms resistor.

Light painting is an interesting photography technique in which we use long exposure in low light conditions and then draw using a flashlight or other objects that emit light, so that the resulting photo will contain all the movements and shapes we did with flashlight.

My purpose was to build a high power LED torch with the possibility to hang it from a chain or string so I could spin it or rotate it fast enough to draw an orb or other objects and still getting a bright result in the photo, because a typical LED torch or flashlight works well when trying to draw letters or lines in the light painting, because we move slowly, but when we move the flashlight much faster, the lines and spirals look much weaker, that’s why is useful to use high power LEDs, to see the light painting clearly. In addition, the batteries would add more weight at the end of the string, facilitating the spinning of the torch.

The electrical circuit is very simple, basically there’s a 5ohms resistor and 3 SMD LEDs in parallel. The LEDs work at 3.8V with a power consumption of 350mA, but in this case I used a little higher resistor so the LEDs could still make more light, but I prefered a longer battery duration.

The circuit is divided in three small PCBs with one LED in each one, to illuminate in three different directions during the light painting.

To attach a string to the LED torch, I’ve added a M3 screw in the top part, but I still have to find an appropiate string or chain to use.

To make an orb with light painting you have to spin the LED torch with your wrist while you rotate slowly around yourself. This will create the effect of some sort of sphere, you can find a lot of examples of this technique.

I still haven’t tried it properly, I hope to post a new photo using this tool soon in my photography section, thanks for reading.